1. Field of the Invention
The present invention relates generally to a liquid crystal display with a smoothing film and method for forming the same.
2. Description of Prior Art
In an age of visual information, considerable interest is concentrated on a medium of information transfer, an image display. As a result of the interest, various flat-type displays replacing an existing cathode ray tube are developed and rapidly popularized.
The technical progress of a liquid crystal display having thin, light and low consumption power characteristics, and driven by low voltage is remarkable, and the liquid crystal display has been widely used in display monitors for vehicles or in the screen of color televisions as well as in display monitors for lap-top personal computers or pocket computers.
Using such characteristics material having the dielectric anisotropy is oriented on the electric field, and the picture is displayed in the above-mentioned liquid crystal display. FIG. 1 is a view illustrating a general structure of a liquid crystal display in prior art.
Referring to FIG. 1, the liquid crystal display includes a front plate 1a and a rear plate 1b stuck to each other by a sealing material applied on the edge of them to form a predetermined closed space where liquid crystal is injected, transparent electrodes 2a, 2b formed on inner surfaces of the front plate 1a and the rear plate 1b in a predetermined pattern, alignment films 4a, 4b disposed on upper portions of the transparent electrodes 2a, 2b and aligning a molecule of the liquid crystal injected into the closed space in a predetermined direction. Insulating layers 3a, 3b are formed between the transparent electrodes 2a, 2b and the alignment films 4a, 4b, and spacers 6 are formed in the closed space to keep and control a gap between the front and rear plate 1a, 1b.
The alignment films 4a, 4b formed in the upper portions of the transparent electrodes 2a, 2b are formed as follows. The alignment films 4a, 4b are laid inside the front plate 1a and the rear front 1b whereon the transparent electrodes 2a, 2b are formed in a predetermined pattern by spinning or offset printing. Thereafter, the alignment films 4a, 4b are treated with a predetermined heat and surfaces opposite each other are rubbed at a predetermined angle in order to align the molecule of the liquid crystal in the predetermined direction.
At this time, referring to FIG. 2, the insulating layer 3a or the alignment film 4a of the front plate 1a is not uniform due to a height difference between a portion with electrodes and a portion without electrodes. Because of a trend toward a display of high quality, the above-mentioned problem has been given serious consideration. As the display device is bigger and finer, indium tin oxide transparent electrodes for driving the liquid crystal need low resistance electrodes, 5 to 15 .OMEGA./cm.sup.2. As the resistance of the indium thin oxide film is lower, the electrodes have a film with a thickness of more than 2000 .ANG.. since the alignment characteristic of the alignment film dispersed on the electrodes is different according to the height difference, the bad quality of the liquid crystal display occurs. Moreover, as numbers of pixel are densified, the height and length difference of the indium tin oxide electrode 2a between pitches increases. As a result, the indium tin oxide electrode and the alignment film must be flat.